Lost in the theming process of bbpress 2.0.2

I have run into some problems while theming bbp-twenty ten on my site. BBpress is installed, The forum fits within my custom theme after changing the template files. But some CSS does not seem to stick and my forum got issues with padding/margins and width or height at many places.

I’m not asking for help on how to learn CSS I know that perfectly fine. I would just like to be pointed to some documentation or information on how to mkae it possible to theme bbpress. Maybe someone personally got this very same problem and could help me out with some hints.